The available science on molds and their potential health effects remains under study, but considerable progress has been made. The U.S. Centers for Disease Control and Prevention (CDC), the Institute of Medicine of the U.S. National Academy of Sciences, the World Health Organization and Health Canada all agree that living or working in a building with mold damage results in increased risk of respiratory disease. Although there are several guidance documents available, there are no accepted national or international standards for mold investigation, evaluation or remediation. AIHA, however, has worked to translate the advice from the previously mentioned government agencies into state-of-the-art inspection and sampling protocols, such as AIHA’s
Recogni​tion, Evaluation and Control of Indoor Mold​ book, also known as the "Green Book." If properly used, these methods are suitable for assessing hidden contamination and directing essential visual inspections. For health outcomes, there are no available exposure assessment methods that can provide useful information for individuals. This is primarily due to the fact that each person’s response to mold exposure is unique.

The scientific complexities surrounding this issue would be a huge challenge but the truth is that other, less scientific, difficulties dwarf them. Media attention on this topic often creates emotionally charged circumstances, making scientific and professional judgment, as well as reasoned dialogue on this subject, very difficult. In some instances, building owners have been known to ignore or dismiss potentially serious problems. Many indoor air quality (IAQ) problems have nothing to do with mold, and buildings seldom have only one indoor environmental quality problem. It is essential to consider multiple sources of building IAQ problems instead of focusing on just mold concerns. In other instances, building occupants or public officials armed with mold sampling reports of dubious quality have reacted with alarm to potential threats, making risk communication very difficult.

The information on this page represents a consensus statement by a group of experts about important aspects of the state of the science. The guidance offered is practical information based on years of experience addressing mold issues, and this document does not claim to be a definitive or comprehensive position statement. Because it is not comprehensive, it should always be used in conjunction with other existing guidance documents, as well as professional judgment by qualified consultants and public health officials.

Public and occupational health practice is rarely an exact science. Prevention always poses the challenge of making tough and often costly decisions with incomplete information or understanding.

Information and Resources

When significant mold or other sewage contamination has occurred, it is recommended that business and homeowners seek professional guidance before attempting to clean large amounts of contaminated materials. Industrial hygienists and other safety and health professionals can anticipate health and safety concerns and design solutions to prevent exposures using guidelines established by governmental agencies and institutions such as the Institute of Inspection Cleaning and Restoration Certification. The following agencies and organizations have guidance related to mold response:

American Industrial Hygiene Association (AIHA)

The Centers for Disease Control and Prevention

Federal Emergency Management Agency

Canadian Centre for Occupational Health and Safety

U.S. Environmental Protection Agency

National Institute for Occupational Safety and Health

U.S. Occupational Safety and Health Administration